Open Stack

So, I observe a consensus here of "long migrations suck"m +1 to that.
I also observe a consensus that we need to get no-downtime schema changes
working. It seems super important. Also +1 to that.

Getting back to the original review, it got -2'd because Michael would like
to make sure that the benefit outweighs the cost of the downtime. I
completely agree with that, so far we've heard arguments from both Jay and
Boris as to why this is faster/slower but I think some sort of evidence
other than hearsay is needed. Can we get some sort of benchmark result that
clearly illustrates the performance consequences of the migration in the
long run?

-Mike



On Thu, Oct 24, 2013 at 4:53 PM, Boris Pavlovic <boris at pavlovic.me> wrote:

> Michael,
>
>
> >> - pruning isn't done by the system automatically, so we have to assume
> it never happens
>
>
> We are working around it
> https://blueprints.launchpad.net/nova/+spec/db-purge-engine
>
>
>
> >>  - we need to have a clearer consensus about what we think the maximum
> >> size of a nova deployment is. Are we really saying we don't support
> >> nova installs with a million instances? If so what is the maximum
> >> number of instances we're targeting? Having a top level size in mind
> >> isn't a bad thing, but I don't think we have one at the moment that we
> >> all agree on. Until that happens I'm going to continue targeting the
> >> largest databases people have told me about (plus a fudge factor).
>
>
> Rally https://wiki.openstack.org/wiki/Rally should help us to determine
> this.
>
> At this moment I can just use theoretical knowledges.
> (and they said even 1mln instances in current nova implementation won't
> work)
>
>
>
> Best regards,
> Boris Pavlovic
>
>
>
> On Fri, Oct 25, 2013 at 2:35 AM, Michael Still <mikal at stillhq.com> wrote:
>
>> On Fri, Oct 25, 2013 at 9:07 AM, Boris Pavlovic <boris at pavlovic.me>
>> wrote:
>> > Johannes,
>> >
>> > +1, purging should help here a lot.
>>
>> Sure, but my point is more:
>>
>>  - pruning isn't done by the system automatically, so we have to
>> assume it never happens
>>
>>  - we need to have a clearer consensus about what we think the maximum
>> size of a nova deployment is. Are we really saying we don't support
>> nova installs with a million instances? If so what is the maximum
>> number of instances we're targeting? Having a top level size in mind
>> isn't a bad thing, but I don't think we have one at the moment that we
>> all agree on. Until that happens I'm going to continue targeting the
>> largest databases people have told me about (plus a fudge factor).
>>
>> Michael
>>
>> --
>> Rackspace Australia
>>
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>> OpenStack-dev at lists.openstack.org
>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
>>
>
>
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